... with performance and installation benefits Product descriptionModified Bituminous Underlayment is a hybrid product created from asphaltic ... Combining the best of both products, Modified Bituminous Underlayment boasts a lightweight material that is easy to ... 1500gfMD≥1500gfLow temperature flexibility≤23Fheat resistance≥185F waterproof underlayment Verified Information This information is Verified by ...